Rising atmospheric concentrations of CO 2 ( C a ) can reduce stomatal conductance and transpiration rate in trees, but the magnitude of this effect varies considerably among experiments. The theory of optimal stomatal behaviour predicts that the ratio of photosynthesis to transpiration (instantaneous transpiration efficiency, ITE ) should increase in proportion to C a . We hypothesized that plants regulate stomatal conductance...

The quickly rising atmospheric carbon dioxide (CO 2 )‐levels, justify the need to explore all carbon (C) sequestration possibilities that might mitigate the current CO 2 increase. Here, we report the likely impact of future increases in atmospheric CO 2 on woody biomass production of three poplar species ( Populus alba L. clone 2AS‐11, Populus nigra L. clone Jean Pourtet and Populus × euramericana clone I‐214). Trees were grow...

To determine whether globally increasing atmospheric carbon dioxide (CO 2 ) concentrations can affect carbon partitioning between nonstructural and structural carbon pools in agroforestry plantations, Populus nigra was grown in ambient air (about 370 μmol mol −1 CO 2 ) and in air with elevated CO 2 concentrations (about 550 μmol mol −1 CO 2 ) using free‐air CO 2 enrichment (FACE) technology. FACE was maintained for 5 years. Af...